The project goal is the design, construction and preclinical testing of advanced microwave applicator systems for hyperthermia treatment of deep-lying cancers. In our preliminary work applicators for internal introduction of microwave heating fields by electromagnetic syringes and through catheters such as stomach tubes have been shown to be feasible, as have external systems employing conformal microstrip antennas or arrays of miniature wave guide applicators and bolus techniques to focus the fields. We propose to study these devices theoretically and experimentally in a special "phantom" facility, and optimizing the design, evaluate and calibrate the deep heating performance of the systems in in vivo animal experiments.